Low precession gyroscope



Oct. 14, 1952 M. EDELSTEIN 2,613,538

LOW PRECESSION GYROSCOPE Filed Feb. 2, 1949 s Sheets-Sheet 1 POWER SUPPLY 27 mcwome AMPLIFIER AND MODULATOR INVENTOR. MURRAY i. EDELSTEIN ATTGRNEY.

1952 M. l. EDELSTEIN LOW PRECESSION GYROSCOPE Filed Feb. 2, 1949 3 Sheets-Sheet 2 INVENTOR, I 1. EDELSTEIN MURRAY AZ'IURNEY.

4, 1952 M. I. EDELSTEIN 2,613,538

LOW PRECESSION GYROSCOPE w Ifi'ill r m m H g m INVENTOR.

MURRAY I. EDELSTEIN www- ATTORNEY.

Patented Oct. 14, 1952 LOW PRECESSION GYROSCOPE Murray I. Edelstein, Columbus,0hio, assignor to Curtiss-Wright Corporation, a corporation of Delaware Application February 2, 1949, Serial No. 74,215

The present invention relates to an improved gyroscope for use in aircraft control systems and other systems where a stablereference platform isfneeded.

The principal purpose of the invention is to provide a support for a spinning gyroscopic mass which will impose upon it a minimum of frictionalconstraint, to the end that it will continue to spin with a minimum of precession and at a substantially constant speed without continued application to it of any substantial driving force.

f" This purpose is accomplished by supporting the spinning mass upon a power driven rotor which is spinning at substantially the same speed and in substantially co-axial relation with the gyroscopic mass, with the result that either no movement or only slow movement between the mass and the rotor can occur. A moving fluid film, preferably a film of any suitable gas (here- I inafter referred to as air) is employed to supspin the gyroscope rotor, are not applied directly to the gyroscopic mass as they are in conventional power driven gyroscopes; and only the torques incident to support of the gyroscopic mass itself are applied to it.

The invention provides a releasable coupling between the power driven rotor and the gyroscopic mass whereby the latter may be brought up to operating speed together with the rotor and then may be uncoupled for continued spinning substantially independent of the rotor.

Means are also provided whereby during such continued rotation any angular departure of the rotor axis from coincidence with the axis of rotation of the gyroscopic mass is sensed and corrected by means which cause return of the rotor into such axial coincidence. The sensing apparatus may be of any suitable type, its specific form not being a part of the present invention.

However, the invention contemplates the inclusion of someform of sensing apparatus which will impose no appreciable constraint upon the gyroscopic mass, one example of an apparatus of this kind being the photo-electric means described hereinafter. The sensing apparatus may serve to control power operated means which 13 Claims. (01. 74-537) either act directlyon the rotor to restore it to the axial coincidence with the gyroscopic mass; or, if the rotor itself has gyroscopic characteristics, imposes forces upon it which cause it to precess into such coincidence.

The foregoing and other objects and advantages will become apparent from the following description of the apparatus shown in the accompanying drawings, wherein:

Fig. 1 is a plan view; Fig. 2 a cut-away perspective view; Fig. 3 a fragmentary sectional view taken approximately along line Y--Y of Fig. 1; and Fig. 4: a schematic view of the means for maintaining substantial coincidence of the spinning axes of the rotor and gyroscopic mass.

As shown, the apparatus comprises three main parts: a stator ll gimbal mounted for universal angular movement upon a base l2, 9. power driven rotor l3 journalled to spin within the stator, and agyroscopic mass 14 of generally spherical form supported by the rotor for rotation therewithin. The stator constitutes a housing for the rotor and comprises a cylindrical body section 15 and end membersylB and. H, the end members carrying anti-friction bearing means 18 which journal the rotor. Extending from opposite sides of stator section I5 are trunnions l9 and 20 journalled in anti-friction bearings 2| carried by a gimbal ring 22. The latter in turn has trunnions 23 and 24 extending from the opposite sides thereof, the axis of trunnions 23 and 24 being transverse to that of trunnions l9 and 20. Trunnions 23 and 24 are supported in anti-friction bearings 25 carried by upright supports 26 extending from base I2.

transmitting to the aircraft control system (or to whatever other system employs the apparatus) the position of the stator relative to base I2 about the X-axis. Another motor, 29, is carried by the gimbal ring 22 and is connected to trunnion I9 forapplying to it torque urging rotation of the stator and rotor about the axis; of trunnions l9 and 20, designated the Y-axis. Also carried by the gimbal .ring and connected to trunnion 20 is a servo device 30, similar to device 28, for sensing and transmitting to the aircraft control system the position of the stator relative to the base about the Y-axis.

'An air turbine is employed for spinning the rotor upon an axis, designated the Z-axis, that is normal to both the X-axis and to the Y-axis. The turbine comprises nozzles 3| mounted on the stator end members l6 and I1 and arranged to direct jets of air against buckets 32 provided on the end faces of rotor I3. The air is delivered to the nozzles from manifold rings 33 secured to the end members I6 and I1, and the latter have openings34 through which the air may exhaust from the stator after it leaves the buckets 32. The air supply system leadin to the manifold rings 33 includes an air inlet nipple 35 on one support 25, the nipple being adapted for connection to a compressed air line and opening into an annular passage in the support around the trunnion 24. An axial passage through the trunnion connects the annular passage with one end of a, tube 31 secured to the gimbal ring, the opposite end of the tube communicating with an annular passage 38 surrounding the trunn on 20. The latter has an axial passage communicating with annular passage 38 and also with branch passages 39 leading along the stator to the manifold rings 33, as is shown in Figs. 2 and 3.

The rotor I3 comprises upper and lower halves 40 and 4| which together enclose a spherical chamber, whose center is at the intersection of the X, Y and Z ax6S,,containing the yroscopic mass [4. The latter while of generally spherical form has non-spherical polar surfaces of which the upper one is flattened to provide a reflecting face 42 that forms a part of the photo-electric means to be described hereinafter and of which the lower one is flattened to form a face 43 adapted to cooperate with clutching mechanism also to be described hereinafter.

The spherical mass I4 is supported within the rotor chamber on a thin film of air. This film is maintained by air entering the rotor chamber under pressure from a multiplicity of passages 44 located at spaced intervals around the chamber, the air after traversing a portion of the space between the sphere and the rotor exhausting through multiple passages 45. The latter discharge from the rotor into the interior of the stator, the discharged air finally escaping from the stator into the outside atmosphere through the stator openings 34. The friction of air flowing along the surface of the sphere from any one inlet passage 44 to an adjacent outlet passage 45 will, of course, exert a force on the sphere acting to rotate it inthe direction of the flow. For this reason the passages 44 and the passages 45 are preferably so arranged that airflow in one direction is substantially balanced by another airflow in theopposite direction to the end that no appreciable torque in, any direction will be exerted on the sphere by the air bearing means when the sphere has no motion relative to the rotor.

The means for conducting air to passages 44 includes an air inlet nipple 41 carried by one of the fixed supports 26 and adapted for connection Fluid communication to an air pressure source. between this nipple and passages 44 is successively through an annular passage 48 in the fixed support, a passage through trunnion 23 leading into and through a tube 49 secured to the gimbal ring 22, an annular passage 50 around trunnion I9,

an axial opening through the trunnion into and through atube I secured to the stator II, a passage 52 in a bottom closure plate 53 of the stator I I, an opening 54 in a rod 55 into a cylinder chamber 56 in the lower rotor half 4|, and thence through passages 51 into the multiple air inlet passages 44.

A pressure plate 58 is mounted by an anti-friction bearing 59 upon the upper end of rod 55, the latter being supported in the lower half of the rotor for sufiicient sliding movement relative thereto along the Z axis to carry the pressure plate into and from engagement with the adjacent surface of the sphere I 4. The rod has spaced shoulders 60 and BI and slidable upon it between these shoulders is an annular valve 62 whose peripheral surface is slidable on the wall of cylinder 56. A compression spring 63 in the cylinder chamber beneath the valve urges the latter toward its uppermost position wherein it closes the air passages 51 from the cylinder chamber, and, by abutment with shoulder BI, transmits the upward pressure of the spring to the rod so that the plate 58 is pressed against the face 43 of the sphere. The spring force is great enough to hold the sphere and rotor against relative motion while the rotor is being accelerated to its operatin speed by the turbine means hereinbefore described. When air pressure is applied to the upper end of the cylinder through passage 52 the valve will bemoved downwardly to uncover passages 51, to provide the air for the air bearing system, and, almost simultaneously to engage shoulder for holding the pressure plate 58 away from the sphere. A vent 54 from the lower part of cylinder chamber 56 to the outside of the rotor prevents build-up of pressure against the under surface of the valve in the event of air leakage past the valve.

The photo-electric means for controlling the motors 21 and 29 include a light source 59 mounted within a casing member 64 on the stator for directing light against the flat face 42 of the sphere, and photo-electric cells 63, BI, 62 and 63, also mounted within the casing, responsive to light reflected from the face 42. Cells 60 and GI for controlling the X-axis motor 21 are disposed on opposite sides of the Z-axis and are spaced from each other in the direction of the X-axis, while cells '62 and 53 for the Y-axis motor are also disposed on opposite sides of the Z-axis from each other and are spaced from each other in the direction of the Y-axis. The cells are connected to amplifying and modulating means which control the supply of electric current to the motors. As shown diagrammatically in Fig. 4 the cells 60 and GI are connected by respective leads 65 and 66 and by a common lead 61 to a unit 68 which constitutes a power supply and control for the motor 2?, the latter being shown schematically as having forward field windings 69 and reverse windings l0. Electric currents generated by the cells are amplified in the unit 68 and employed by suitable modulating means within the unit to control the current supply to the motor, to the end that forward motor winding 69 is energized when cell 50 generates a greater current than cell 6!, and that reverse motor winding 10 is energized when the opposite is true.

The arrangement of the photo-electric means is such that when the face 42 of the sphere I4 is normal to the Z-aXis of the rotor equal quantitles of light from source 59 will be reflected on cells 60 and GI. The cells will accordingly generate electric currentsof equal value and opposite polarity with the result that no motivating current will pass through the motor. Should the stator (which carries the light sourceand the photo-electric cells)v become displaced relative to sphere I4 about the Y-axis, say in a clockwise dito apply a tionfwill'occur should sure plate 58, cause unit withthe' rotor.. operating. speed has been attained the source of of the'light source and cells relative to therejfiector' surface 42 will result in an increased amnunt of light being reflected onto cell '60 and a "decreased amount being reflected onto cell 6|. Accordingly cell 60 will generate a greater current and the forward motor windings 69 will therefore beenergized, a causing the motor 21 H U torque through the trunnion 23 and stator I I to the rotor Win the direction which,

assuming that the rotor is being spun by the turbine means, will cause the rotor to precess about the Y-axis in a counter-clockwise directionf This application of torque by motor 21 will continue until the motor is de-energized by reason jof the Z -axis having been returned by the precession of the rotor into a position normal to surface. A similar but reversed corrective acthe stator becomedisplaced in the opposite direction. The Y-axis motor 29 'ils-co'iitr'olledby the photo-electric cells 62 and 63 byfmeans which may be substantially identical td' those Just described in connection with the cellsfio and 6| and the motor 21. indicated hereinbefore the details of the,

means for sensing departures of the rotors Z-axis fr'oiirthe axis of rotation of the sphere M and for-thereby controlling the motors 21 and 29, are not-a part of the present invention. Hence these nieans have been illustrated herein only in a schematicmanner, and it will be understood that their-invention contemplates the use of any other suitable sen'sing'and control means which are found to be suitable for the same purpose.

Operation of the gyroscope is started by open- 'iri" .;athe'source of compressed air to the nipple iioonne'cted to the turbine means 3 I, 32, thereby bringing the rotor [3 up to its operating speed.

'Diiring thetime while the rotor is being accelerated, the source of air to nipple 41 is shutoffywith the result that the spring and presthe sphere 14 to spin as a When the desired constant air .to nipple isopene'd,v causing retraction of the pressure. plate 58 and establishment .of the air. bearing film between the rotor and the sphere, thereby. uncoupling the latter and allowing-it to spin about its axis of, rotation with almost .no

'constraintbytherotor to angular movement in any direction.

In the event that the short axis of thesphere .(the axis thereof normal to its polar .faces 42 and 43).:isinclined relative to. the Z-axisgabout which therotor spins when coupled to the rotor, immediately, upon the, uncoupling centrifugal forceswill act to tilt the sphere to bring its short H axisinto coincidence with the Z-axis.

- .So long as the axis of rotation of the sphere .remains coincident with the rotors Z-axis, the photo-electric sensing and control means will keep the motors 21 and 29 de-energized, so that they impose no V torque on the rotor, with the result that it will act as a conventional gyroscope, tending to which sense and transmit; to the gyroscope controlled system the -angular position of the base I2 relative to the -rrotors Z-axis.

Precession of the rotor will result in inclination of the Z-axis from coincidence to effect rotor precession in a direction which precess slowly as a result of torques .imposed by friction of bearings 2i and 25, and by the servo devices 28 and 30 'will return the rotor into axial coincidence with the sphere.

It will be seen that whenever the Z'-axis is inclined relative to the axis of rotation of the sphere some relative motion between the spinning rotor and sphere willoccur, and that this motion will result in a certain amount of friction between the rotor and'the sphere which will effect precession of the latter. However, with a photo-electric or other type of control apparatus for motors 21 and 29 which is responsive to small angular displacements of these two axes,"the relative'motion between the rotor and sphere is very slow in relation to its rotational speed. Accordingly the air bearing imposes little frictional conits inherent gyroscopiccharacteristics insofar as they are effective upon the stator. In such case precession resulting from torque applied by motors 21 and 29 cannot be employed to restore invention otherwise than as may be the rotor axis into coincidence with the axis of the sphere I4 (or equivalent gyroscopic mass) and the motors must therefore be arrangedto move'the rotor into such axial coincidence.

It will beunderstoodfurther that the principles of the invention are applicable tojgyroscopes 'of various" other forms than that described hereinbeiore and that such gyroscopes may be employed for'many diiierent purposes where a reference platform that is relatively stable in space is desired. 'The disclosure of one preferred form of gyroscope in the foregoing description and accompanying drawings is therefore 'm'a'de by way of illustration of the inventive principles involved and not byway of limitation, there being no intention to limit the scope or application of the required by the appended claims. i

I claim as my invention:

1. A gyroscopic device comprisingi a basefa stator mounted on the base and a rotor journalled to spin on the stator, the mounting of the stator on the base providing for universal angular movement of the rotor axis relative to the base; a substantially spherical mass arranged within the rotor with its center coincident with the center of said'universal angular movement, said mass being supported by the rotor for universal movement relative thereto about said center; means for spinning the rotor aboutyits axis; means for sensing departures of the-rotor axis from the axis of rotation of said mass; and means controlled by the sensing means in response to such departure for acting upon .the rotor but not upon said mass to return saidaxes into coincidence. v

2. A gyroscopic device comprising: a base, a stator mounted on the base and a:rotor journalled to spin on the stator, the mounting of the stator on the base providing for universal angular movement of the rotor axis relative'to the base; a substantially spherical mass arranged within the rotor with its center coincident with the center of said universal angular movement, said mass being supported by the rotor for universal movement relative thereto about said center; means for spinning the rotor; 'means' for sensing departures of the rotor axis from'the the stator to apply forces to the rotor-to cause it to return by precession into co-axial relation with said mass. M

'3. A gyroscopic device comprising: a base, a stator mounted on the base and a rotor journalled to spin on the stator, the mounting of the stator on the base providing for universal angular movement of the rotor axis relative to the base; a; substantially spherical mass arranged within the rotor with its center at the center of said universal angular movement, said mass being supported by the rotor for universal movement relative thereto about said center; means for spinning the rotor about its axis; means for sensing departures of the rotor axis from the axis of rotation of said mass; and means controlled by the sensing means in response to such departures for reacting between the base and the stator to return the rotor into co-axial relation with said mass.

4. A gyroscopic device comprising: a base, a stator mounted on the base and a rotor journalled for rotation on the stator, the mounting of the stator on the base providing for universal angular movement of the rotor axis relative to the base; a substantially spherical mass arranged within therotor with its center at the center of saiduniversal angular movement, saidmass being supported by th rotor for universal movement relative thereto about said center; means for driving the rotor about its axis; means for "sensing departures of the rotor axis from the axis of rotation of said mass; and means controlled by the sensing means in response to such departures for reacting between the base andthe stator to apply forces to the rotor to cause it'to return by precession into co-axial relation with said mass; and a releasable drive connection between the rotor and said mass, whereby said mass may be rotated with the rotor by the driving means and may then be released for rotation independent of the rotor;

5. A gyroscopic device comprising: a base, a

stator mounted on the base and a rotor journalled for rotation on the stator, the mounting of the stator on the base providing for universal angular movement of the rotor axis relative to the base; a substantially spherical mass arranged within the rotor with its center at the center of said universal angular movement, said mass being supported by the rotor for universal movement relative thereto about said center; means for driving the rotor about its axis; means for sensing departures of the axis of rotation of the rotor from the axis of rotation of said mass; and a releasable drive connection between the rotor and said mass, whereby the latter may rotate with the rotor to be brought to operating speed by the driving means, and may then be released for rotation independent of the rotor. 6'. A gyroscopic device comprising: a base, a

- stator mounted on the base and a rotor journalled for rotation on the stator, driving means for said rotor, the mounting of the stator on the base providing for universal angular movement of the rotor axis relative to the base; a substantially spherical mass having flattened poles and arranged within the rotor with its center at the center'of said universal angular movement, said ..rotor having passages for admitting fluid to pro- -vide a fluid film to support said mass for universal movement in and relative to the rotor about said center; means operated by reflection of light from one of said flattened poles for sensing departures of the rotor axis from the axis of rotation of said mass; means controlled by said sensing means in response to such departures for acting upon the rotor but not upon said mass to return said axes of rotation into coincidence; a member carried by the rotor and engageable. with the other one of said flattened poles of said mass to cause the latter to rotate with the rotor and with its axis of rotation coincident .with that'of the rotor in bein brought to operating speed by said driving means; resilient means for urging said member into such engagement; and fluid operated means for disengaging said member to release said mass for independent rotation and for simultaneously directin fluid through said passages to provide the aforementioned fluid film.

7. In a gyroscopic device, a first rotatable mass mounted so that its axis of rotation may have universal angular movement, a second mass having its center of gravity coincident with the center of said universal angular movement, said second mass being mounted upon the first mass for in its center of gravity coincident with the center of said universal angular movement, said second mass being mounted upon the first mass for universal movement relative thereto about said center, and a releasable drive connection between said masses-whereby after being brought to operating speed by rotation with the first: mass the second mass maybe released for independent rotation. 1 c 9.. In a gyroscopic device, a rotatable member mounted so that its axis of rotation may have universal angular movement, said member having a chamber with a spherical wall portion, a substantially spherical mass supported and arranged within said chamber, means providing a fluid film for supporting said substantially spherical mass for universal movement upon said spherical wall portion, said mass having a flattened polar surface, and means responsive to displacement, of said surface from normal relationshipto'the axis of rotation of said'member for acting upon said member but not upon said mass to restore said relationship.

10. In a gyroscopic device, a rotatable member mounted so that its axis of rotation may have universal angular movement, said member having a chamber with a spherical wall portion, a subtion of the mass whereby upon being uncoupled from'said member axis.

11. In a gyroscopic device, a rotatable member mounted so that its axis of rotation may have universal angular movement, said member having a chamber with a spherical wall portion, a subit will rotate about its'polar stantially spherical mass arranged within said gchainber. means providing a fluid film for sup- "porting said substantially spherical mass upon 'said spherical wall portion, means responsive to departure from coincidence of the axes of rota: tionf-oi said member and said mass for acting upon said member but not upon said mass to {restore said axes to coincidence, releasable means 'or'coupling the mass to said member for rotaw nas a unit therewith, and said mass havingfa' ghtened polar portion whereby upon being un- -coupled from said member it will rotate about its polar axis.

12. In a gyroscope, a stator and a gimbal mounting therefor providing for stator movement bout first and second axes disposed transversely fto each other, a rotor mounted on the stator for rotation relative thereto about a third axis ex- 'i'tending normally to said first and second axes, "drive means for spinning the rotor about said :third axis, a gyroscopic mass mounted upon the [tor for angular movement relative "thereto bout at least said first and second axes, means "I orapplying torques to the stator for effecting novement of the stator and rotor about said first" nd second axes, and means responsive to angular "displacements of the axis of rotation of the gyro- "gscopic mass relative to said third axis for causing operation of the torque applying means in direcplatform, a stator supported On a universal mounting on said platform, a rotor journaled on said stator so that the rotor axis has universal angular movement relative to said platform, a gyroscopic mass having a generally circular contour enclosed within said rotor and having its center of gravity coincident with the center of said universal angular movement, means for coupling said mass to said rotor, means for spinning said rotor and thereby bringing said mass up to corresponding speed, said mass being uncoupled from said rotor when desired gyroscopic speed is obtained whereby said mass can rotate freely within the spinning rotor, sensing means responsive to departure of the rotor axis from the axis of rotation of said mass, and means controlled by said sensing means for acting on said rotor to restore coaxial relationship of said axes.

MURRAY I. EDELSTEIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,603,352 Paxton Oct. 19, 1926 1,639,233 Paxton Aug. 16, 1927 1,890,831 Smyth Dec. 13, 1932 1,986,807 Gillmor Jan. 8, 1935 2,091,963 Carlson Sept. '7, 1937 2,517,612 Varian M Aug. 8, 1950 

